From owner-freebsd-current@FreeBSD.ORG Wed May 14 00:15:51 2014 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 2F3E8315 for ; Wed, 14 May 2014 00:15:51 +0000 (UTC) Received: from mail-qg0-x22b.google.com (mail-qg0-x22b.google.com [IPv6:2607:f8b0:400d:c04::22b]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id E5B7B2009 for ; Wed, 14 May 2014 00:15:50 +0000 (UTC) Received: by mail-qg0-f43.google.com with SMTP id 63so1616559qgz.16 for ; Tue, 13 May 2014 17:15:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=uVvPjh1uzUJOGQyv4LHxGO49JPGMlb2rJmBLfkGqPQw=; b=VTFCisLYrTYYVxm7sn6ab/Bp7PT91GVqhklus26WBQ4SOUIwECiX7htJ89/lgm9CN3 jdbu95erHydY8ifstt3Upf5BVZkQZ0E+4/9eWGuIskjffz5m/PSZEx8nXThzd5Hfd8A7 rRsg9j4EW5hwqa8Ng6UIPzivIO26WUPQP7iUrzhuKMNJcK2CIuY2O4tzjokdvBI9N0wE VNsFZvccNdQFq3ikcDrM1xXt8Yv/i6ziJR0TTn9yJ/nnqxCg2nA0h1fdRdRLrRFxUmJ7 JfZL148733itZekfQn810hF6V6MTqRfsWqvrQ7TkzVkRT+WEj2jlq1Dq9ZX1D2YvXsP2 T3ng== MIME-Version: 1.0 X-Received: by 10.140.49.208 with SMTP id q74mr200777qga.103.1400026550154; Tue, 13 May 2014 17:15:50 -0700 (PDT) Sender: adrian.chadd@gmail.com Received: by 10.224.191.201 with HTTP; Tue, 13 May 2014 17:15:50 -0700 (PDT) In-Reply-To: <53729FBC.5060204@aldan.algebra.com> References: <53729FBC.5060204@aldan.algebra.com> Date: Tue, 13 May 2014 17:15:50 -0700 X-Google-Sender-Auth: kE9gcBNZU32HDRHbQmKtdPcmr0o Message-ID: Subject: Re: Locking console with Ctrl-S hangs various processes (ttydcd) From: Adrian Chadd To: "Mikhail T." Content-Type: text/plain; charset=UTF-8 Cc: Current FreeBSD X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 14 May 2014 00:15:51 -0000 Hi! This sounds rather silly and should be fixed. Yes, hanging the vty shouldn't hang the console device. Would you / your friend mind filing a PR? Thanks! -a On 13 May 2014 15:42, Mikhail T. wrote: > Hello! > > A fellow FreeBSD user was recently confounded by a problem: various processes on > his 10.0 system were hanging or otherwise misbehaving: su, certain daemons, syslogd. > > They were all hung in the "ttydcd"-state. Searching > for that revealed only, that > other people have seen the problem, but nobody (including the entire > freebsd-stable@ on 2012 > ) was > able to offer a solution. > > Apparently, the problem stems from the ttyv0 (which moonlights as /dev/console > for the vast majority of installs) being locked -- such as by pressing Ctrl-S. > One needs not be a root to do it... > > After that, any attempts to write to /dev/console -- which even syslog(3) often > does -- would hang the calling process until the tty is unlocked (such as with > Ctrl-Q). > > This may be the desired behavior for "normal" ttys, but, perhaps, /dev/console > should act differently? > > -mi > > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org"